Forming limit diagram of perforated sheet

Baik, Seung‐Chul; Oh, Kyu Hwan; Lee, Dong Nyung

doi:10.1016/0956-716x(95)00349-z

Cited by 20 publications

(26 citation statements)

References 12 publications

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“…Note that this criterion reasonably predicted the lower bound of the FLC of a perforated Invar sheet for a dot-type shadow mask. 14 The FLC was shaped like combined lines, monotonically decreasing from a strain path with a negative minor strain to the equi-biaxial stretching. Figures 12 and 13 demonstrate that neither of the plastic instability criteria is appropriate to characterise the formability of the perforated aluminium sheets with square holes.…”

Section: Predicted Flcsmentioning

confidence: 99%

Forming-limit prediction of perforated aluminium sheets with square holes

Chiba

Takeuchi

Nakamura

2015

The Journal of Strain Analysis for Engineering Design

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The forming-limit strains of perforated aluminium alloy (AA5052-O) sheets with square holes were theoretically and experimentally estimated for two types of hole arrangements: square and triangular patterns. The theoretical forminglimit curves were obtained by finite-element analyses on a unit module of the perforated sheets using two different approaches: the phenomenological theory and crystal plasticity theory. Hill's quadratic anisotropic and von Mises yield functions were used for the phenomenological analysis, and the one-element-per-grain model was adopted for the crystal plasticity analysis. To determine the forming limits, two different types of plastic instability criteria were applied. The experimental forming-limit strains were also obtained through a Nakazima stretching test. The theoretical predictability of the forming-limit curves was assessed by comparing the theoretical and experimental results. The comparison demonstrated that (1) the plastic instability criterion based on the external force power predicted qualitatively the same forming-limit curves as the criterion based on the equivalent plastic strain of the ligament for both hole arrangement patterns and (2) although the shapes of the predicted forming-limit curves were in reasonable agreement with the experimental results, the level of the predicted limit strains was considerably higher than that of the experimental limit strains. Thus, it was found that neither of the plastic instability criteria previously proposed for perforated sheets is appropriate to characterise the formability of perforated aluminium sheets with square holes.

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Section: Predicted Flcsmentioning

confidence: 99%

Forming-limit prediction of perforated aluminium sheets with square holes

Chiba

Takeuchi

Nakamura

2015

The Journal of Strain Analysis for Engineering Design

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“…During forming the perforated sheets deformed plastically. Before and after forming, the distances between two equivalent points along longitudinal (major) and transverse (minor) directions were measured in the necked region [25]. The major true strain (ε 1 ) and minor true strain (ε 2 ) are then calculated using the formulae given in Eqs.…”

Section: Forming Limit Diagrammentioning

confidence: 99%

“…The deformation behaviour of perforated sheets during metal forming operations is different from that of plain sheet metals and this had been studied by chen and coworkers [18,19] and baik et al [20][21][22]. In attempt to study the formability of perforated sheets, Yi-Che Lee et al [23] developed yield criterion for perforated sheets in terms of apparent stresses by employing the equivalent-continuation approach.…”

Section: Introductionmentioning

confidence: 98%

Modelling the correlation between the geometrical features and the forming limit strains of perforated Al 8011 sheets using artificial neural network

Elangovan¹,

Narayanan²,

Narayanasamy³

2010

Int J Mater Form

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In the recent years, sheet metals are produced with perforations in various shapes and patterns to improve the appearance of sheet and to save weight of components. As in conventional metal sheets, it is important to form the perforated sheet metals also within their safe strain regions to avoid the forming failures like necking, fracture and wrinkling. The Forming Limit Diagram (FLD) is an appropriate tool to determine the forming limit strains. The limiting strains of perforated sheet metals mainly depend on the geometry of the perforations and forming variables. This leads to large increase in number of test to be conducted with various geometry and forming variables for determining the forming limit strain for perforated sheets. Aiming to reduce the number of experiments needed, in this work, an Artificial Neural Network (ANN) model has been developed for forming limit diagram of perforated Al 8011 sheets based on experimental results and correlated with the geometrical features of the perforated sheets. This model is a feed forward back propagation neural network (BPNN) with a set of geometrical variables as its inputs and the safe true strains as its output. This ANN model can be applied for prediction of FLD of perforated sheet having any geometry.

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“…The perforated aluminium sheets are used in variety of applications including automotive, acoustics, architecture, interior design, displays, manufacturing, safety flooring, agriculture, pollution control, transportation, and mining etc (http://www.perforatedsheet.net/perforatedsheet/uses.html). A number of theoretical treatments have been developed to study the plastic behavior of perforated sheets (Chen, 1993;Baik et al, 1995;Baik et al, 1997;Baik et al, 1997;Lee and Chen, 2000). Conversely, there are very few reports on the experimental studies on formability of perforated sheets.…”

Section: Forming Of Perforated Sheetsmentioning

confidence: 99%

“…During forming the perforated sheets deformed plastically. Before and after forming, the distances between two equivalent points along longitudinal (major) and transverse (minor) directions were measured in the necked region (Baik et al, 1995). The major true strain (ε 1 ) and minor true strain (ε 2 ) are then calculated using the formulae given in equation (1) and (2) respectively.…”

Section: Forming Limit Diagrammentioning

confidence: 99%

Application of Taguchi approach on investigation of formability for perforated Al 8011 sheets

Elangovan¹,

Narayanan²

2010

Int. J. Eng. Sci. Tech

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Sheet metal forming is a vital manufacturing process used in the automobile, aerospace, agriculture and architecture industries. The sheet metal is formed to various shapes to make useful components. The perforated sheets replace the solid sheet in some applications because of aesthetic appearance and low weight compared to solid sheet metal. The ability of the sheet metals to be formed into various shapes without failure is termed as formability. The formability of perforated sheet depends on chemistry of the material, the forming parameters, dimensions of the perforations and ligament width. In this paper, the forming limit diagram for perforated Al 8011 sheet of 1mm thickness has been evaluated and the influences of the diameters of perforations and ligament widths on the forming limit strains have been studied. The ligament width is the most influencing factor which has the percentage contribution of 70.04 and 72.55 in Tension-Compression, 69.65 in Plane strain and 51.49 and 71.84 in Tension-Tension conditions. This work gives reasonable forming limit plastic strains of the perforated sheets with various combinations of the diameters of perforations and ligament widths and also gives the prediction of these strains by varying it.

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Forming limit diagram of perforated sheet

Cited by 20 publications

References 12 publications

Forming-limit prediction of perforated aluminium sheets with square holes

Forming-limit prediction of perforated aluminium sheets with square holes

Modelling the correlation between the geometrical features and the forming limit strains of perforated Al 8011 sheets using artificial neural network

Application of Taguchi approach on investigation of formability for perforated Al 8011 sheets

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